F1 is really annoying but sadly nothing of all these worked for me. I use ubuntu and still when I press F1 it brings up the GNOME terminal manual window!!! Any thoughts?

If it brings up Gnome help and not Vim help, it means your Gnome window manager snatches it before Vim has a chance to see it. The solution, if any, is somewhere in your Gnome (and/or WM and/or Compiz and/or ...) settings. — Tonymec 17:37, April 9, 2010 (UTC)

Ok Τonymec thank you very much. Finally what I did to fix it is the following. First of all with xev utility I found out that the keycode of F1 is 67. Then I issued the command xmodmap -e "keycode 67 = Escape". That was it. F1 behaves like Escape now